SummerTale
by Galaxina-the-Seedrian
Summary: (PnF/UnderTale AU); Phineas and his friends, while being stalked by the bust-lustful Candace, fall into Mt. Ebott, where none has ever managed to escape; so legends go. Upon falling, the group is separated, and Phineas finds himself on a search for his beloved friends, while being guided by a single voice. "Phineas! Wake up! You are the hope of all humans and monsters!"
1. Chapter 1: Phineas

**Okay, I don't think I really need to explain this one; I mean, I just put Phineas in Frisk's place because, one, he's my little marshmallow, and two, he has a striped shirt just like Frisk and all the kid monsters anyway. So it was only natural to pick someone like Phineas, even though Ferb would've been a good choice, too. Even though I think that Frisk kinda reminds me of a girl, I still think Phineas is the best and most obvious choice.**

 **Take this into notice; I have NEVER played the game, ever. I've only watched let's plays, because my parents do not allow me to indulge myself in something like UnderTale for religious purposes. BUT THEY WILL NOT STOP ME FROM WRITING THIS FIC! XD Anyways, I'll try to be accurate, but this IS a Phineas and Ferb twist to it; I wanna make it kinda like an episode.**

 **Note this, however, I will not be doing any yaoi or yuri shipping (NEVER AGAIN!), again, because of religious purposes; that's why Alphys is gonna be a dude in this fic…please don't kill me. It's just an AU. I can get away with small changes like that. O_O I do not judge anyone who ships Undyne and Alphys. I thought Alphys was a dude at first anyway, tbh, until I saw she had eyelashes.**

 **Metaton stays the same, though…cuz…I have no idea what they are. And they're a robot/ghost, so I don't really judge 'em. XD**

 _Phineas and Ferb are owned by Dan Povenmire and Jeff "Swampy" Marsh_

 _Undertale is owned by Toby Fox©_

 **So, without further ado, I introduce you, the PnF spin to UnderTale:**

" **SummerTale!"**

 **Enjoy~! X3**

 **P/F/P/F**

 _Long ago, two races ruled over the Earth:_

 _ **HUMANS**_ _and_ _ **MONSTERS**_

 _One day war broke out between the two races_

 _After a long battle, the humans were victorious_

 _They sealed the monsters underground with a magic spell_

 _Many years later…_

 **(~)**

 **Chapter 1: Phineas**

 _ **MT. EBOTT**_

 _ **201X**_

Upon finally reaching the top, Phineas breathed in what he called pure, fresh air. The sun beat brightly down on him and his fellow companions, who were still following him up. He had been overly excited, of course. He looked back out at his hometown, the shining bright city of Danville, with a grin.

 _Seeing your hometown shine in the sun this way…fills you with_ _ **determination.**_

Phineas nodded, yes, this was a perfect view. Another prefect start to a great adventure ahead of them. Phineas peered down the mountain, and called out, "C'mon, you guys, we're wasting daylight!"

Yes, he was most definitely far too excited for this.

At least, to Baljeet's interest. Speaking of him, he was miraculously the first to pop his head up over the mountain; although, this could be because he had been launched over by none other than Buford, a large, fat boy, who followed soon after. Baljeet flew over Phineas' head, and landed smack down on the dirt floor, with his mouth open. He gagged immediately, wiping the dirt and grass off of his mouth. Buford laughed boisterously at the nerdy child, while Phineas simply watched on obliviously to the "joke" before looking back to see if the others were anywhere near their destination.

"Augh…Phineas," Baljeet said in a small voice, "Are you sure this is such a good idea? I mean…don't you remember the legends-?"

Phineas was too distracted, of course, reaching out to another friend, Isabella, who nearly tripped up it seemed. "Gotcha!" Phineas grinned, "You okay?"

Isabella gratefully nodded at her 'rescuer'. "Yes," she answered, "Thank you so much, Phineas."

Phineas wasn't able to hear Ferb, his step-brother and the last to reach the top of the mountain, snort at Isabella's gratitude. Even though Phineas, oblivious as he was, wasn't able to really tell, Ferb knew very well that Isabella had 'tripped-up' on purpose to gain the attention of the boy of her dreams. Phineas did, however, notice the eye roll he gave, but didn't seem to detect the meaning.

Phineas, who seemed to be the leader of the group in spite his height and obvious immaturity, rubbed his hands together. "Alright," he said, "Is everyone here? Ferb?"

Ferb gave his brother a thumbs up.

"Isabella?"

Isabella raised her hand up, high and proud. "Present!"

"Baljeet?"

Baljeet's eyes shifted nervously; my, they were very high up, weren't they? "Uh…presently punctual…heh…"

"Buford?"

Buford pounded a fist onto his chest. "As if I would miss the many antics of Phineas and Ferb," he scoffed, snickering.

Phineas grinned at Buford's response in particular, clearing his throat. "Perry?"

Everyone paused to look around for their one missing companion. Phineas blinked. "Uh…say, where _is_ Perry?" the boy wondered, "Ferb, I thought he was with you?"

Ferb looked around before giving a simple shrug. Isabella gave one as well, voicing, "Maybe he just didn't want to come along? I mean, I don't blame him; he's only a platypus, and this _is_ Mt. Ebott."

Baljeet shuddered at the name of the said mountain. He looked to Phineas, who seemed to be nodding at what Isabella had told him. "Uh…why are we doing this again?" the nerd asked.

Phineas looked to Baljeet, very, very glad that he asked. "Adventure," Phineas stated, "We've lacked that in our lives for a while now, what with everyone being so protective. Especially our sister, Candace; I know it's terrifying, mysterious, and over all dangerous, but that's probably just what we need after…uh…certain events."

Buford and Isabella nodded vigorously at Phineas, both equally excited about the prospect. Phineas looked to Ferb, who simply blinked at him. Strange. Why did Ferb seem a little nervous? They were usually on the same page…

Baljeet rose and eyebrow, frowning deeply. "Phineas, please, do not tell me this is an act of rebellion against your older sibling," he said, rubbing his arm awkwardly.

Phineas frowned. "What?" he tilted his head, "Of course not! Why would that be? I just want to see if the legends are true. Everyone talks about it so much it was bound to be explored by someone."

"It _has_ been explored," Baljeet said, "And…you remember what happened to _them_ , right?"

Phineas sighed. Yes, he did remember. Who wouldn't know it? Everyone knew of this legend by now. It was practically taught in schools.

Phineas smiled calmly once again. "We're different," he stated, "We've done the impossible! We've survived a shattering city! We've explored unimaginable places! Heck, we've built a rollercoaster, time machine-"

"Alright, alright, I get it," Baljeet sighed, and added with a grumble, "I still wish you invited me to the time machine ploy…"

"Point is," Phineas stated, "We've done things no one else our age has ever done before! We can do pretty much anything we set our minds to; now, what do you say everyone? Whose with me?!"

"I am!" Isabella was the first to answer, practically singing as she slid over to the side of her future boyfriend.

"Me," Buford walked over to Phineas, nodding.

Against his better judgement, Ferb nodded his head as well, and put an arm around his brother, who returned the gesture with a large grin.

Everyone stared at Baljeet, who sighed. Baljeet extended his arms towards their destination; a large mouth to a mysterious looking cave. "Are we really going to risk our lives just to debunk a legend?!" he shrieked, "I do not think this is a good idea!"

"Welp, it's four out of five," Buford snickered, "So we outnumber your choice. Now, c'mon, nerd, we've gots some exploring to do."

Baljeet groaned as he proceeded to follow his friends into the cave, as slowly as he possibly could. He paused, and thought, wait, he could just turn back and climb down the mountain. It wouldn't be his fault if his friends-…wait…that's why he decided to come, wasn't it? Baljeet face-palmed at his own morality, and followed them into the cave.

The group with properly prepared, bringing bags of supplies with them. It seemed that their plan was to spend the night there like a camp out. Phineas and Ferb, to answer Baljeet's worries about the safety of such a feat, brought with them a pop-up tent of their own design, which was roomy, and could protect them from virtually anything. Everyone was carrying their own flashlight, looking around as they ventured forth.

"This is cool," Isabella grinned, taking out a handbook from what appeared to be thin air, "Stalagmite and stalactite, flowstone…this is one heck of a cave! I'll get my spelunking patch for sure!"

Phineas looked around, pointing his flashlight up. "Hm…no bats," he smiled, "Sorry Ferb. We brought the bat repellant for nothing. Hm…there seems to be a lot of plant life in here though…so many leaves and vines…"

Ferb, who had gone ahead of everyone, didn't seem to notice his brother's words. Phineas stared off after him, and soon he and the others managed to catch up to him. Phineas blinked at his brother. "Ferb?" he asked.

The green haired both pointed forward. "Look," he simply said, and everyone did as he said.

The group had immediately met up with a large, gaping hole, almost as big as the town square. Phineas, Ferb, and the rest looked on with surprised gazes, and looked up high and low. For such a dark area, it seemed to be light enough to see even without their flashlights, almost as if there was something trying to light up the room. Baljeet looked very nervous. "This looks…promising," he said, though obviously not meaning a thing; he was terrified, "I think we're done here…"

"Ah, c'mon, 'Jeet," Phineas grinned, walking over to the hole, "This is great!"

Isabella, Ferb, and Buford followed after Phineas, while Baljeet stared on in terror. "Are you kidding me?!" he shrieked in a hiss, "You do realize this is where people fell, right? This place it cursed!"

"Enchanted, Baljeet," Ferb corrected, making Phineas smile even brighter than before.

"Two lines in one day!" Phineas applauded his brother, "That's quite the talkativity, bro!"

Baljeet cringed. "Talkativity is not a word," he muttered before reluctantly following his friends over to the hole, "Look, I am just saying that we are going to be in so much trouble if-."

"Baljeet, Baljeet," Phineas shook his head, walking over to her nervous friend to pat him on the back, "We'll be careful. What's the worst that could happen?"

The sound of someone clearing their voice behind them answered Phineas' question, to which all the children froze. Slowly, but surely, the group turned to see the lovely, terrifying, Candace Flynn, who was staring at them menacingly as she crossed her arms, tapping her foot. Beljeet glared at Phineas flatly. "Told you…" he sighed.

Buford grumbled, the most disappointed of them all. "Great," he muttered, "Here comes the fun police…"

Candace gave a look that seemed wicked to any child. She pointed at them with a grin. "Aha!" she said, "I caught you red handed!"

Phineas paled. "Uh…hi…sis," he chuckled, "I know what it looks like, but-."

"I knew I'd find you here!" Candace stated, roughly poking her younger brother on the chest, "Mrs. Garcia-Sharpio said you were off playing adventurers again; said that you were 'pretending' to go to Mt. Ebott."

Phineas winced along with his friends, save for Baljeet, who was just glad that true disaster had been averted. Candace glowered darkly. "You guys are in so much trouble," she scowled, "Get your butts out of here before you get hurt!"

"Aw, c'mon, sis-!"

"No!" Candace crossed her arms sassily, "Absolutely not! Of all the places you brats could've been exploring, it had to be here?! Really?!"

Phineas stepped back, looking over to his friends for support. They didn't seem to have the strength to say anything, and shrunk back. Phineas looked over to Candace. "We were going to be careful," he assured his older sister, "We know how dangerous this is. We came prepared."

Ferb, Isabella, and Buford raised up their bag of supplies into the air. Buford elbowed Baljeet, who sighed and did the same. This only intensified Candace's rage, and the children stepped back once again. Candace rubbed her temples, sighing. "If mom and dad were here," she muttered more to herself than to anyone else, "You guys would be so busted…" then she grinned meanly, "Of course, _I'm_ in charge now, aren't I? So, in fact, you guys are indeed, _busted!"_

Candace looked to Isabella, Baljeet, and Buford with a knowing smirk. "Oh-ho, I can't wait to see what your parents do to you," she snickered, then glared at her brothers, "As for you two-!"

Candace seemed to be rambling on about something, but Phineas didn't pay any mind. He instead decided to listen to a more, appealing voice that seemed to call to him. He closed his eyes in bliss. The voice sounded so nice…then his eyes opened.

Wait. What was it saying?

Phineas, without any warning, turned around, pushed passed his friends, and peered into the hole, much to Candace's annoyance and shock. "PHINEAS!" she shouted, stomping over to him, "WHAT ARE YOU DOING?!"

"I hear something…" Phineas squinted his eyes, "I think…I see something…it's a small light…maybe there really is something down there…"

Phineas became mesmerized by the idea that, perhaps, the legend was real after all. He grinned. "Hello~? Anyone down there~?" he called, making Candace and Baljeet shriek.

Candace grabbed Phineas by the collar of his shirt and pulled him back, glaring harshly. "I swear, if I didn't show up, you guys probably would've fallen down that hole," she said, "You idiots…we're going home, now!"

Phineas, to Candace's surprise, struggled in her grasp. She growled. "Phineas, what are you doing?!" she pulled on him, "C'mon, we're leaving!"

"I think someone's down there," Phineas said, "Maybe they need help?"

"I don't care," Candace scoffed, "They asked for it, I say! We're leaving, Phineas!"

Phineas didn't listen. He continued to struggle in his sister's grip as she tried to drag her brother away. Everyone else sadly, or in Baljeet's case gladly, followed, Buford still muttering that a good excursion had been wasted yet again by the ever annoying teenager. Yet Phineas, refused to give in. That voice…it was faint, but…familiar…

Finally, even before they could reach the path back, Phineas broke free of Candace's grip, and started to book it towards the hole. Candace followed immediately, with his friends also running after him, Isabella and Buford cheering their friend on, while Baljeet seemed to be scolding Phineas, and Ferb remained ever stoic to the situation.

"PHINEAS!"

Phineas only wanted to hear that voice, to make out what it said, but in his own hast he managed to snap his foot in one of the vines and tripped, heading straight into the hole…

…Or would've, if it were for Ferb, immediately sprinting over to rescue his brother. He managed to grab the younger boy by his legs, letting him dangle a bit. Phineas sighed in relief. "Thanks, Ferb," he chuckled again, "I…got carried away…"

"Yes," Ferb nodded, "Yes you did."

Just as Phineas was about to point out just how much Ferb was chatting away, suddenly a vacuum-like force seemed to activate, as it began sucking at Phineas and Ferb's grip. Ferb's body began to slide towards the hole, even as he tried to stand to resist it. Isabella and Candace went over to assist Ferb, followed by Baljeet and Buford, but the force of the hole was too great and their grip on the solid ground was too feeble.

"What's going on?!" Candace shrieked in panic, "Phineas and Ferb, what did you do?!"

"I-I don't know," Phineas said, "Keep holding on! Don't le-!"

Before Phineas could finish, Buford slipped, and everyone found themselves plummeting into the abyss, their screams echoing throughout the cave.

 **(~)**

 _Legends say that those who enter the mountain never return…_

[End of Chapter]

 **A/N:**

 **Well, hope you guys enjoyed! X3 'Cause updates are, more than likely, going to be slow as usual. If any of you have ideas to speed up the process, I'll be glad to hear them.**

 **I am so excited to see where this train-wreck goes!**

 **-GTS**


	2. Chapter 2: Flowey

_**Jass114:**_ Very interesting predictions. I like them! :3 Of course, you may be surprised with how they end up and my reasoning behind the choices~. Regardless, I hope you enjoy future chapters.

 _ **Britt30:**_ Well, here you go, another chapter! Thank you for reviewing!

 _ **Marissa Flynn:**_ Eeyup. I decided to go all out. Here's to actually getting this done! (drinks from a bottle of ketchup like a bottle of beer)

 _ **ROCuevas:**_ Thanks! Hope you like this next chapter. X3

 _ **Rebecca Webb:**_ IT SHALL BE (so many ideas, so little time, squee~)! And I hope you enjoy the rest of the story! Thank you for reviewing.

 **(~)**

 _Phineas and Ferb are owned by Dan Povenmire and Jeff "Swampy" Marsh_

 _Undertale is owned by Toby Fox©_

 **Enjoy~.**

 **P/F/U/T**

 **Chapter 2: Flowey**

 **(~)**

 _For as long as he could remember, Phineas loved the thrills of adventuring. It didn't matter where he was, whether it be in the supermarket, within the city, a mysterious forest, he liked looking for new things to see and do. He had this quirk ever since he got lost in the town square at the age of three; Candace was still getting the hang of being responsible, apparently. Many would assume that a child would fear losing their way, but not Phineas. He was excited, like he had always been about what the world had to offer him._

 _Really, he was like any little brother out there. Sweet but annoying, innocent but…well…perhaps he wasn't entirely like other little brothers. Some would say that he was pure, but such a thing didn't exist. He was too trusting, too naïve; he didn't seem to understand that there were bad people in the world, or that "bad" was even a real thing in the fabric of the universe. Maybe that's why he didn't take anyone's warnings seriously and simply waved it off as them worrying too much. Part of him wanted to prove how silly they were being, h_ _ow silly his sister was being in particular._

 _But they had their reasons, Phineas had thought at one point, they must have some form of reasoning behind their fear. Maybe something he didn't understand? He read all the history books about the monsters that nearly wrecked the world, and how they were sealed away into the Underground…_

… _So what else was there to be afraid of?_

 **(~)**

The giant hole was like an empty void, cold and lifeless. The breeze Phineas felt was created through the velocity of the drop. He felt himself spinning in the air when it first happened, and all else fell into place later. He knew as well as anyone else that he was probably going to die.

Phineas screamed as he descended from above, flailing his arms and legs forward in a circular motion as if that would slow down his fall. It had felt like hours had passed since he and his companions had been sucked into the dark pit of which none could escape. He didn't pay any attention to anything else around him but below, where a light glowed and seemed to be burning brighter and brighter. The boy braced himself.

"LOOK OUT! AH!"

 _Thud!_

 _Boing!_

Phineas lightly bounced up and down on what felt like a cushion that had easily broken his fall. The bouncing flipped him over due to his panic as he struggled before he found himself staring up at where he had fallen, sunlight somehow lighting up through the tunnels of the cave and into the abyss that Phineas had fallen into. He panted slowly, calming down before he assessed the area he was in before a lovely aroma filled his nostrils with delight.

It was dark, but he could see clearly that he had fallen into a patch of beautiful yellow flowers that glistened in the light's rays. Phineas slowly sat up, trying his best not to ruin the plants. "Someone must've planted them," Phineas realized as he crept off of what appeared to be a garden, "Did I…crush any?"

He looked at the flowers and, miraculously, they were unharmed. He sighed in relief and wiped his brow. "Good," Phineas sighed, "I would've felt terrible if we crushed them. They look so nice…guess this is how people would survive their fall down here, but…I wonder…"

Phineas looked around again, finally noticing that he was alone. Ferb, Candace, and all his friends were now missing, nowhere to be found. Phineas looked around, feeling his chest tighten up. He was sure they had fallen with him. Where could they be?

"I-I guess I wasn't paying attention," Phineas thought, "Hm…oh! That's it! I'm probably lighter than everyone else, heh, so laws of gravity state that they fell before I did."

Phineas nodded, congratulating himself for his reasoning before pausing. "…But if that's the case, why aren't they down here?" he wondered to himself, "Where could they…?"

As the boy fell into thought once again, he noticed something stretching out in the light. A grey floored pathway that led to a large ominous looking door. It looked like it was expertly crafted with stone and granite, which seemed to be darkened from the lack of proper lighting. Phineas didn't complain, nor did he praise the architect, but instead came to the obvious conclusion that his friends and family must've gone ahead of him through there.

He didn't seem to take time to wonder why they didn't wait for him, or why going through such a terrifying looking door was a good idea. Phineas didn't really care.

 _The thought of finding your missing friends and loved ones…fills you with_ _ **determination**_ _._

Phineas nodded at his resolve and headed forward, venturing through the short hallway. The boy looked around to see that he could not see any walls beside him, nor did he want to reach out to feel them for fear of falling into yet another abyss. He reached the door, and upon further inspection noticed a strange symbol painted above the doorframe.

Phineas tilted his head at the white inscription before staring at the door that seemed quite ancient. He opened the door, with some difficulty due to the mass of the door. It truly was made out of stone and granite; it felt so smooth, and cold. On the other side was nothing but more darkness. It made Phineas freeze up and close the door.

"Augh…there's no way I'll be able to find my way through…" Phineas shook his head, "No. I gotta go. I gotta catch up with my friends."

The boy opened the door again, flashing a confident grin before feeling his face fall with surprise as a single spotlight shone from the heavens onto a small, yellow flower, much like the garden he had landed on. Phineas stared before he walked forward to look at the lonely looking specimen before hearing the door behind him suddenly shut. Somehow he knew there was no going back after this.

Phineas swallowed hard and stepped closer to the flower slowly but surely. A sense of wariness filled the air, which he could barely understand to be perfectly honest. It was only a flower after all.

A flower with a friendly smile, humming patiently as he waited for Phineas to…wait…wait a second…

Phineas stopped to take another good look at the flower that appeared to be _staring_ at him with small black eyes. It had a big smile on his face, looking very pleased with its visitor. Before Phineas could wonder if he was imagining things, it spoke to him in a friendly, cheery voice.

"Howdy!"

Phineas flinched back in surprise as the creature greeted him like a normal person would. "I'm **Flowey** ," the plant said, " **Flowey** the **Flower**."

The boy hesitated at first as he stared at the creature…the small, harmless looking flower. Phineas smiled, brushing off his worries, but couldn't quite push them far enough away to not be feeling something. "Hi, I'm Phineas Flynn," he introduced, "You can call me Phineas if you like."

Flowey nodded. "Nice ta' meet'cha!" it tilted it head, humming a bit, "Hm…you're…new to the **Underground** , aren'tcha?"

Phineas looked at the plant weakly. "Actually," he said, "I kinda fell down here on accident with my friends. We were exploring Mt. Ebott when we-."

Phineas was trailing to be honest, thinking on how they ended up in this mess to begin with and how it was probably his fault, and was actually thankful that Flowey seemed to cut him off. "Aren't you a little," the flower twisted its body in a way that would break an ordinary flower's stem; instead, the plant's 'body' seemed akin to a snake's, coiling almost as he gave an upside down stare to Phineas, " _Young_ to be exploring a place like Mt. Ebott?"

Phineas nodded. "Yes, yes we are," he stated, "We get that a lot."

Flowey's body straightened up immediately, a small pop being heard that made Phineas jump a little. "We…ooh, wait a minute. So you're saying that there are…others in here?"

Phineas nodded again in response. Flowey felt its eyes light up as Phineas mentioned _them_. Its grin seemed to grow, excitement filling its being. Phineas looked confused, but smiled at the plant's enthusiasm. "Ooh~, really?" Flowey giggled, "More new friends? That's certainly new, tee-hee!"

Phineas blinked. "New…?" he asked, "So…there have been more people…"

Flowey lowered its head. "Yeah," it said, sounding a little solemn, "They usually come… _ **alone**_ …to be honest…hm…but where are your friends?"

Phineas frowned at this. "I'm sorry," he said, "They're not with me right now. I don't know where they are to be honest. I just landed here a few minutes ago."

Flowey raised its head back up and gasped at the boy as if he were a pitiful creature. It shook its head back and forth, tsking. "Golly," Flowey said, "You must be so confused!"

Phineas nodded at this with an admitting shrug. Flowey gave another smile to Phineas. "Someone ought to teach you how things work around here!" it stated matter-of-factly, "I guess little old me will have to do."

"Are you sure?" Phineas asked, walking a bit closer; suddenly, the air of nervousness filled him once more, but…why? "I wouldn't want to impose if-."

"Nonsense!" Flowey stated, "I'm the one offering, aren't I? Besides, you've done me a big favor by coming here. It gets _boring_ down here, ya' know?"

Phineas nodded as if he understood. Well, maybe he did, actually. Being in a dark room by yourself didn't seem all that social to him. Phineas smiled. "Okay," he said, "So…what do I do?"

"It's simple, really," Flowey said, "First, you must expose to me your **soul**."

"…My **soul**?" Phineas tilted his head, "That's not really a physical object."

Flowey giggled at Phineas' response. "Of course," he realized, "How stupid of me! I never seem to learn; you humans haven't used your **souls** in," a word seemed to be censored out, Phineas realized; he could've sworn that he heard Flowey say **fight** , "years. Here, it's easy! Just summon it with your thoughts and emotions."

Phineas blinked, looking down to his chest and squeezing his hands into fists as he began to focus on the very thought of his **soul** , feeling it take shape from his body into the air. Phineas opened his eyes as he felt a warmness cultivating in the room like a lamp. Floating in front of him was a red glowing heart. The boy stared in wondered.

"Whoa…"

Flowey nodded happily at this. "Very good!" it said, "See that heart? That is your **soul** , the very culmination of your being. Your **soul** starts off weak, but can grow strong if you gain enough LV."

Phineas raised his hand, making Flowey chuckle lowly. What a child, Flowey thought, mentally shaking its head. "Yes?" Flowey asked.

"What's LV stand for?" Phineas lowered his hand, tilting his head once again.

"Why, **LOVE** of course!" Flowey said as if it was obvious, yet no hint of malice seemed to be evident.

Phineas smiled at this, rest his shoulders as he slouched a little. "That…that sounds nice," he admitted, "I kinda thought for a second that…phew…"

Flowey gave a playful smirk to the boy. "You want some **LOVE** don't you?" he asked knowingly, "Don't worry. I'll share some with you!"

The flower winked at the boy, who felt very happy for some reason. Why did it feel so forced? He seemed fine in this creature's presence, yet…

Five small floating objects floated above Flower, aiming directly at Phineas' **soul** from a distance. Flowey looked to Phineas instructively. "Down here, **LOVE** is shared through…" Flowey turned his head away strangely, "Little white…' _friendliness pellets'_."

"Friendliness pellets…?" Phineas looked at the flying objects as Flowey simply nodded to him.

"Are you ready?" Flowey asked, "Move your soul around, and get as many as you can!"

"Uh…how do I-?"

"Just gotta focus. Don't worry. Relax, and fly into the pellets. 'Kay?"

Phineas watched the pellets fly over to his soul and nodded at the flower obediently. Using his very being, he managed to move his **soul** towards the white friendliness pellets. Flowey watched on carefully, earnestly, excitedly…then it impacted with one of the pellets.

Phineas suddenly felt his lungs weaken as an indescribable pain filled him, causing him to fall to his knees, clutching his chest. He wheezed as he stared up at his **soul** , which protruded cracks around it upon hitting one of the pellets. He looked over to Flowey quizzically and froze in fear as Flowey's face contorted into a monstrous looking grin, his black eyes growing while his now bore sharp teeth to match the soulless stare. Phineas found himself shrinking down until he felt smaller than the flower in front of him.

"F-Flowey…what's…?"

" _You idiot,_ " Flowey said, its voice contorting into something horribly contrasting to the pleasant sound from before, " _In this world, it's kill or_ be _killed!_ "

Phineas looked utterly confused and terrified. "Wh-what are you talking about?!" he shrieked and moaned as he reached for his **soul** , "How do I put it back?! What's going on?!"

As Phineas started throwing a flurry of questions at Flowey, the plant simply let out an cruel laugh as if it were rubbing its nonexistent hands together maniacally, proclaiming, " _Why would_ _ **anyone**_ _pass up an opportunity like this?!_ "

Suddenly, Phineas saw his **soul** being surrounded by several 'friendliness pellets', which by now started to look more and more like bullets. He realized then that he had been tricked. He looked to Flowey in realization as his heart dropped. "You…you're a monster!" he shrieked, "You're one of the creatures-!"

" _Oh, so now you figure it out?!_ " laughed Flowey, " _How stupid can you be? Then again, you're not the first to make that mistake! HA-HA! It just never gets old!_ "

Flowey giggled madly as the bullets began to inch closer to red heart, which tried to move around helplessly. Phineas continued reaching out to it, crawling over weakly. "S-stop!" he shrieked out, "I won't-!"

Suddenly, the flower raised its head up triumphantly, screaming out " _DIE!_ " as the bullets suddenly sped up their attack until they were literally a centimeter away from impact. Phineas hid his face, waiting for the inevitable.

Then the bullets disappeared, and Phineas felt fit as a fiddle. The boy opened his eyes to look, and saw a strange looking Flowey simply staring at the scene as if it had expected the boy to die. Slowly, its smile faded into a look of shock as it saw that the **soul** did not wither away like it had hoped. "Wait," Flowey looked to Phineas with widened eyes as the boy stood up so suddenly, "WHAT?!"

Phineas stared at himself; all the wounds that appeared on himself and his **soul** suddenly vanished completely. The boy looked just as confused as the flower did as the heart hovered over to his chest, not really returning to its initial belonging. "I…" Phineas looked to Flowey, whose face contorted into hateful rage that make him squeak.

" _What did you do?!_ " Flowey shrieked, causing Phineas to brace himself for fear of the plant creating another attack, " _What part of_ _ **die**_ _do you not under-?!_ "

Before Flowey could finish its sentence, a ball of fire suddenly knocked it to the side, sending it flying into the darkness with a surprised gasp. Phineas stared at the direction the foul creature with an amazed stare. The boy stared for a while until he heard the footsteps of his apparent rescuer, and looked over towards yet another monster.

 _Great…_ Phineas sighed, _Another one…wait…did…did it just-?_

The monster didn't look menacing to say the least. It looked like a giant compared to himself, and was a little taller than most adults. It wore attire that was akin to a purple dress, and noticed a symbol on the chest of its outfit looking much like the symbol above the door he walked through. He blinked and looked up to the creature, who he realized was a monster that looked much like an anthropomorphic goat. Its face was full of concern that seemed to melt away Phineas' fears.

"What a terrible creature," it said to the boy, walking over to him and kneeling down to check if it was injured or not, "Torturing such a poor, innocent youth…"

Phineas blinked silently at the monster, who seemed to be inspecting him. It was making Phineas feel very uncomfortable, to say the least. The monster obviously realized this, and flashed him a reassuring smile. "Ah, do not be afraid, my child," it told him, "I am **Toriel** , caretaker of the **Ruins**. I pass through this place every day to see if anyone has fallen down. You are the first human to fall down here in a long time."

Phineas frowned at this. "Wait…the first?" he asked, "Then…then I guess you haven't seen any of my friends? They fell down here, too."

Toriel looked confused at this. "Strange…" the monster admitted, "Those who fall always fall into the ruins…hm…perhaps they have gone through the ruins without my noticing. I will have to seek them out to see if they are alright. They could be hurt."

Since the creature looked more feminine and gender defined, the boy chose to call it a "her" instead of making the monster out to be a mere object. Besides, she seemed nice enough to be considered that. And now that he thought about it, Phineas never realized that monsters acted so much like humans in the first place. He thought they were more like ravaging animals. That's how some seemed to describe them back at home, Candace in particular.

Phineas began to wonder how his friends were fairing, now that he knew for certain that monsters were in fact still living and breathing down there after all these years.

Toriel gave Phineas another warm smile to him as she motioned forward. "Come," she said, "I will guide you through the catacombs. This way."

Phineas stared up at Toriel and smiled as her, nodding in agreement to follow her. The ominous air seemed to flee with Flowey, and he went to follow the stranger, his only guide, through the darkness. It was a short walk to the other door, which somehow illuminated now that Flowey's presence was gone. Strange, Phineas admitted, very strange.

Toriel entered through the door, and Phineas followed immediately after.

Underneath the spotlight, Flowey seemed to respawn through the dirt, watching the door close behind Phineas. The plant scowled angrily before escaping through the dirt, and venturing through the roots of the underground world. A wicked grin came across the flower's face.

"Now, while those idiots are busy," it giggled, "Let's see if I can find them first…"

 **A/N:**

 **I really hope that this didn't come across as rushed. XD**

 **Also, can I just say how precious goat-mom is? She must be protected at all. Costs. She's just…so pure. So frigging pure. X3**

 **Hope you guys liked it! Please, review, follow, fave, or whatever and have a pleasant day! I also accept critiques, so don't be shy. ^^**

 **Have a God blessed day!**

 **-GTS**


	3. Chapter 3: Toriel

**I'm so sorry that it took so long for me to update; the internet was acting very, very weird and it prevented me from accessing the site.**

 **(~)**

 _ **Jass114:**_ Very interesting question to ask. Personally, I don't think it would work given that Flowey, who literally has no soul, can't actually feel emotions other than the negative ones (apparently). I mean, the "power of friendship" didn't work on him, so I doubt cuteness would, even if it was caused by Isabella being drenched with cuteonium.

 _ **FallsGravitee:**_ Actually, no, he's not. I don't think I'm spoiling much when I say that in-game the ring of bullets automatically disappear without explanation before they even touch you, possibly because of Toriel's intervention; she even heals you as she saves you. Frisk blamed Phineas because he was confused as to what was happening, not because Phineas had anything to do with it.

 **(~)**

 _Phineas and Ferb are owned by Dan Povenmire and Jeff "Swampy" Marsh_

 _Undertale is owned by Toby Fox©_

 **Enjoy~.**

 **P/F/U/T**

 **Chapter 3: Toriel**

 **(~)**

Phineas shut the door behind him gently out of courtesy and turned around to see a purple colored room before him. Looking passed Toriel as she led him forward was a large square of red leaves placed in front of a pile of said leaves lying against a two-way grey stoned staircase that led to yet another doorway. Phineas looked up to see just how tall the place truly was, _the shadow of the ruins looming from above, filling him with determination._ Yet his eyes returned to the square, briefly standing in the center as he proceeded to examine it.

Toriel reached the top of the stone-stairs and looked back to Phineas, noting his curiosity. She smiled, yet her sigh seemed to add to its bitterness. In truth, her heart felt heavy at the sight of the boy standing in that spot. She could not blame his curiosity; many of the children did the same as he did. None of them ever realized…

The goat-monster momentarily waited for Phineas, before sweetly telling him that this was only part of the ruins, and that there was much more to explore. Toriel hadn't the slightest clue why this seemed to excite the child, at least more than most of the children who fell down there, but she couldn't help but laugh either. Such innocence of a child made her feel at peace with the world she lived in.

The two went forth and entered another room, which continued its theme of purple with small dabs of grey being shown on the ground; six patterned buttons of such a color lied on the floor. On the wall just a few feet from the large stubs was a yellow switch with a matching lever. Beside the switch was a door, shut tightly. Toriel waited in front of Phineas as he entered after her.

He looked up at her. "Welcome to your new home, innocent one," Toriel spoke in a much happier tone than her sigh had misled.

Phineas looked around the room unhurriedly, barely noticing the title she gave his…his…

"New…home?"

Toriel flinched at the hint of dread in Phineas' voice, quick to give explanation. "W-why yes," she said, "Haven't you heard of the legend? Those who enter…"

"…They never come out," Phineas breathed, "That's right…even if I find my friends, we're, uh…kinda stuck here regardless, heh…"

Toriel bit her lip as she watched Phineas slightly deflate as the realization seemed to hit him. She didn't know what was harder to watch: the boy's hope falling short, or the fact that he was _still smiling_ , as if he were trying to come up with a positive spin to his current situation. Phineas raised his head up, somehow optimistically. "This place doesn't look that bad," he said, "I mean, I always liked new places. Exploring's kinda my thing."

Toriel watched Phineas for a moment before she cleared her throat to grab the boy's attention again. Not having thought of any words of comfort, such a thing being thought up was impossible at this point anyway, Toriel instead said, "Allow me to educate you in the operation of the **Ruins**. It would at least make living here a little easier for you."

Phineas turned his head back to Toriel's gaze. "How?" he asked.

Toriel proceeded to walk on the buttons, stepping on only a select four of them, and quickly pulled down the lever, effectively opening the door. Phineas watched, and was in awe as the large entry revealed passage.

Toriel walked back to the child, whose curiosity was filling him ever the more. "The **Ruins** are filled with puzzles," she explained, "Ancient fusions between diversions and door-keys. One must solve them to move from room to room. Please adjust yourself to the sight of them."

Toriel immediately proceeded forward before giving Phineas another smile as he proceeded to look at the buttons closer. Even after Toriel left the room, waiting patiently on the other side, Phineas watched the buttons on the floor carefully, going onto his knees. He gave a scrunched look before reaching out, one hand on each of the two untouched buttons. He felt the dust on them, as silence befell the room.

Phineas looked around at the continued nothingness and stood up, walking towards the yellow lever as he tried to pull it. He grunted heavily as he tried to pull it back up to see what would happen, but it would not budge. Phineas looked down to see a sticky substance on the bottom of the lever and he frowned. It was, quite literally, jammed (though, Phineas was sure that, for whatever reason, the substance keeping the lever in place was sap).

Phineas sighed in disappointment, and would've continued on his way if not for the sign on the other side of the door that he had only now noticed. Phineas went over and proceeded to read the inscription. He was amazed that the monsters wrote so elegantly, or at least Toriel or whoever wrote the sign seemed to.

 _ **Only the fearless may proceed.**_

 _ **Brave ones, foolish ones.**_

 _ **Both walk not on the middle road.**_

"Perfect English," Phineas murmured, being far too short to reach up to the inscription.

He shook his head. Of course, given Toriel's accent and choice of tongue, it was obvious that their native speak with English. Why would it be anything else? Phineas rolled his eyes as he went to follow Toriel.

The first thing Phineas saw in the next room was, of course, Toriel, as well as yet another sign hanging from the wall. To his right was a small river which had a bridge reaching over it. The water led to a small opening that no human could squeeze through.

"To make progress here, you will have to trigger several switches," Toriel stated.

Phineas tilted his head, eyeing the opening of the river carefully. Darn his child instincts, making him want to reach in to at least feel what might be on the other side. "Will there be horrible consequences if I choose wrong?" he asked jokingly, a small toothy grin having grown on his face.

Toriel on the other hand took his words seriously, giving a "yes" that made Phineas' witticism fall flat onto his face, replacing his cocky beam lower into a look of bewilderment. In spite giving Phineas a quick look of warning as she answered, Toriel smiled reassuringly afterwards. "Do not worry," she said, "I have labeled the ones you need to flip."

Toriel continued forward, and Phineas immediately went over to the hanging sign to read it. Expecting another daring piece, he was met with a noneventful "Stay on the path". Phineas' lips buzzed flatly, before going back on said path, and walked over the bridge. The path extended to the side, revealing another yellow switch with arrows that were painted onto the wall pointed at it.

Phineas stared, looking over to Toriel patiently standing in front of him with a smile on her face before he went over and pressed the lever. Toriel looked pleased and crossed another bridge with _another_ river under it. Phineas followed, suppressing the urge to stick his hand through the opening once again, and this time saw two levers. Only one had markings pointing to it, and Phineas had the right of mind to go over to it.

Yet, Phineas' curiosity made him briefly stop and glance over to the other lever. Yes, Toriel _had_ specifically told him bad things would happen if he chose wrong, but being a child he never really took danger all too seriously. Without even looking at Toriel to see if she was watching him, he slowly reached for the other lever that wasn't even on the marked path now that he observed closer. "No, no, no!" Toriel said, bringing Phineas out of his temptations, "You want to press the _other_ switch."

Phineas sighed, slumping a bit, which made Toriel laugh a little as he begrudgingly pulled the lever he was supposed to. He heard a strange, sharp noise slide down from behind Toriel that made him turn to her.

"Splendid!" Toriel applauded, "I am proud of you, little one."

Phineas blinked as he walked toward Toriel. _"I only pulled a switch,"_ he thought to himself, _"Would it be rude if I asked her about that?"_

Toriel proceeded to grab Phineas by the hand, pulling him out of his thoughts. "Let us move to the next room," she suggested.

Phineas nodded with a smile. "Okay," he said before Toriel pulled him forward; he looked down to see two large silver panels with strangely shaped holes in the ground squeaked as they stepped on them.

The next room was less extravagant than the other, though turning to the side from his view Phineas saw a practice dummy. It looked vaguely like a monster, yet Phineas couldn't help but think that the figure was supposed to look at least somewhat human. It had no limbs, and it was standing on a wooden post, but the head, as strangely grotesque as it looked, didn't seem monster-like enough for it to be intentional. Perhaps it looked more horse-like than a human, though, now that Phineas thought about it, but…he couldn't help but wonder…

"As a human living in the **Underground,** monsters may attack you," Toriel explained, "You will need to be prepared for this situation. However, worry not! The process is simple."

Phineas frowned, wincing ever so slightly. "I'm…gonna have to **fight** them, aren't I?" he asked (as if it were _obvious_ no less), not noticing Toriel freezing up completely at his words, "My sister taught me a little about fighting, but I'm not that good at it…Ferb is, but he's good at everything."

Phineas looked up at Toriel, noticing her vacant look with a sense of concern. He pulled his hand away from hers, bringing her back. "…Miss Toriel?" he asked, "Are you okay?"

"Oh…oh, yes, my child," Toriel's voice had composure, but it shook in very small doses, "You will _enter_ a **fight** when you come across a monster, but you will not have to hurt them."

Phineas looked surprised; very, very much so. It almost seemed like he doubted Toriel. "I don't?" he asked.

"No," Toriel answered with a smile that seemed to calm her completely as her shivering stopped, "Simply strike up a friendly conversation."

Phineas stared at Toriel for a moment to see if her sanity was still intact. "…Seriously?" he asked, squinting his eyes at her, "I really don't have to kill anything?"

Toriel shook her head. "You will not have to kill any _one_ ," she said, correcting the boy.

Phineas looked back to the dummy. "But…Candace said monsters are ruthless," he said, "She said that they all want to kill humans…"

Toriel gave Phineas a smirk. "Well, if that is true," she said, "Then why haven't I attacked you yet?"

Phineas hummed in thought for a moment. "…I dunno," he admitted, "Why haven't you yet? Are you…" Phineas became a bit wary, "Are you waiting to…?"

Toriel laughed. "Oh, you precious child," she said, "Most monsters are peaceful folk. We mean no harm…or…rather we meant no harm…to be honest, some of us are rather bitter about the end results of the war…but we can be reasoned with, especially with a fellow monster's intervention."

Phineas looked like he was starting to understand now, which pleased Toriel. "Like with what you did with Flowey," Phineas concluded with a smile.

"No," Toriel chuckled, "That was a different case," an annoyed look was cast on her face as she looked to the corner of her eye as if to see if anyone was following them, "This…Flowey… has caused more problems than good. That thing is unlike any monster I've met. But I assure you, as long as I am around to assist, I will be able to protect you."

Phineas nodded at this, but looked back to the dummy with a confused expression. "So…you want me to strike up a friendly conversation, and…?" he tilted his head to the other side.

"Stall for time," Toriel continued, "I will come to resolve the conflict," she nodded towards the lifeless stuffed creature, "Why not try practicing with the dummy?"

Phineas gave a thumbs up to Toriel and went over to the said dummy, with it's beady eyes staring directly at him. Phineas stared at the dummy silently for a moment, wondering exactly what to say. What would one say to a lifeless stuff animal? Phineas thought for a moment longer, and cleared his throat.

"A cotton heart and a button eye," Phineas said in a mock British voice, "You are the apple of my eye."

The dummy stood absentmindedly, not one for conversation. Phineas smiled at this, and turned to Toriel, who looked proud of him. "Ah, very good," she said, "You are very good, Phineas!"

At this point, Phineas realized that the more he was with Toriel, the more she seemed to remind him of his own mother (he really hadn't seen her in a long time, now that he thought about it). He continued to smile brightly. "Thank you, Miss Toriel," he said, nodding his head respectfully.

"Now," Toriel said, nodding forward, "Shall we move on?"

"Yeah," Phineas said as he walked over at Toriel's side, the two of them entering yet another room, "What's next?"

Toriel smiled. "There is another puzzle in this room," she said, "Follow me."

Phineas nodded once again, and obeyed Toriel's command. She giggled a little. "I wonder if you will be able to solve it," she said teasingly.

Phineas cocked a grin as he continued to follow the path behind Toriel, who seemed to stop every time she deemed the child too far behind her. He didn't really mind. He liked Toriel's company anyway. "So…you said the other humans come down here, too?" Phineas asked.

"Not in a while," Toriel said, sounding a little sad, "They've all left the **Ruins** by now…I am curious as to how I never encountered any of your friends."

Phineas nodded. "Yeah," he said, "Maybe they snuck passed you?"

"…Yes," Toriel slowly nodded, "Or…perhaps…"

Phineas waited for Toriel to finish her thought before he felt something lunge into him, knocking him to the floor. Toriel looked back in shock as a frog-like creature angrily pinned down Phineas, who stared up in shock. Human instinct told Phineas to fight back and defend himself from the vile creature. Candace would've probably done it for him if she was here; maybe even Ferb.

But he glanced up at Toriel, who was already running over to assist him, and remembered her words. Phineas coughed. "Uh…you have…nice eyes," he complimented with a nervous laugh.

The frog creature's eyes bobbled silently and Phineas soon realized that they weren't his _real_ eyes. Between the frog's legs was a small, barely noticeable face and blinked at him in confusion. Phineas realized that he didn't understand a thing he said, but was complimented anyway. Before the creature could even smile, however, Toriel and her intense glare came into its vision, and it slid away from them both, fleeing into the hall that they were heading through in fear.

Toriel nodded. "Hmph," she said, "Like I said, they can be reasoned with."

Phineas sat up and stared after the creature. "What was that?" he asked.

"A Froggit," Toriel said, "They're common around the **Ruins**. Do not be afraid of them. They are among the weakest of monsters."

Phineas sighed, shaking his head. _"And yet it managed to pin me down…dang…Ferb was right. I need to work out more."_

"Is something the matter, my child?"

"Hm…" Phineas looked back to the goat-creature with a tiny shrug, "Oh, it's nothing. Lead the way."

Toriel nodded her head and went forward, with Phineas close behind, looking around carefully for more monsters in case they had the same mindset as the Froggit who tackled him initially had. Their walk wasn't much longer, and they almost instantly made it to where they needed to be. Phineas looked from beside Toriel, and saw that the entire flooring that was surrounded by water were covered with sharp spikes that reached up to the bottom of Phineas' long pointy nose. He gulped automatically.

Toriel seemed rather uncomfortable as she looked at the spiked floors. "This is the next puzzle," she said, "But…" her white paw reached down to Phineas as she did before, "Here, take my hand for a moment."

Phineas gripped Toriel's hand as he continued to look at the spikes. Toriel proceeded to walk forward onto the panels. The spikes went into the holes they stuck out of, at shot back up once both Phineas and Toriel went onto another panel. They walked through slowly and strategically through the panels. As Phineas thought, he knew for sure that not all the panels worked like the specific ones were walking on. They reached the other side, onto a wooden platform that lead back to the purple flooring.

Toriel looked to Phineas as she hesitantly released her hold on his hand. "Puzzles seem a little too dangerous for now," she explained softly before walking ahead again.

Phineas looked back to the spiked floor for a while before running after Toriel to the other room. He gave another glance back before reaching back to Toriel's presence once again. This room was much longer than the others, almost a mile long in length. At the end of the room was a large pedestal covered in plant-life.

Toriel looked to Phineas. "You have done excellently thus far my child," she said, "However…I have a difficult request to ask of you."

A long pause passed the room and back as Phineas waited for Toriel to tell him. She frowned. "Uh…hm…actually," she said, "Perhaps this isn't a good idea."

Toriel turned away from Phineas and walked forward in a pace the boy could follow. Phineas blinked, cocked an eyebrow, and jogged over to Toriel. "What?" he asked once he caught up with her, "What is it?"

"Well, I was going to have you walk through this room by yourself to teach you about independence," Toriel explained, "I would've watched from behind that pillar over there, of course, to make sure you were safe…but now that I think this through, you would've been able to see me go behind it in the first place, wouldn't you?"

Phineas nodded. "Probably," he shrugged, "Yeah, its best not to go with that plan."

The two reached the end of the hall, standing by the pillar that was even bigger than Toriel. Phineas, being as smart as he was, decided to point this out and had no idea why Toriel began to laugh. After Toriel seemed to calm down her lungs, a thought occurred to her and she smiled brightly.

"I've a better idea," Toriel said, "I will ask that you stay here alone while I go attend to some business. That will not be a problem to you, will it?"

"Here?" Phineas asked, peering beside Toriel, "But…what about-?"

"-It is dangerous to go on your own," Toriel explained, "The Froggit isn't the only monster in these **Ruins** …ah, I have an idea!"

Toriel reached into the pocket of her dress, and pulled out a familiar device. Familiar in a sense that Phineas knew exactly what it was: a cell phone. Unlike cell phones he had seen, this one looked strange. Why would it have or need an antenna sticking out of it? So strange.

Toriel handed the device to Phineas. "If you have a need for anything," she said, "Just call."

"Oh, sweet, I've never had a cell phone before!" Phineas smile turned into a frown, "Well…there was that one time I did, but I…kinda blew it up…" Phineas quickly looked up at Toriel, "I learned my lesson though! It will not happen again!"

Toriel chuckled, a little concerned. "Let's…hope not, heh," she said, trying to be as polite as possible.

Feeling convinced, Phineas smiled again. "When will you be back?" he asked

"It won't be long, I assure you," Toriel simply said, "You be good, okay?"

Phineas gave a salute to Toriel, who chuckled at the child before walking forward into the rest of the ruins. The boy went over and sat by the pillar, humming to himself as he waited for his friend to come back, examining his new phone curiously as he did.

"Hm…ah, this must be out of date," Phineas realized, "Monsters must have more primitive technology than the humans nowadays. Fascinating…"

Phineas stared at the device for a while before sticking his hand into his pocket, and pulling out a screwdriver. He grinned, and if the phone had a soul of its own it would probably be scared of him right about now. "Let me see what I can do with you…" Phineas mused as he went to work.

 **A/N:**

 **Well…that was boring. XD I am so sorry for making you all wait for this.**

 **Phineas, Phineas, Phineas, you should know better than to do stuff you're not supposed to in** _ **my fics**_ **. Muwahahahahaha…but in all seriousness, if Phineas seems a little OOC to you, do not fret, for this was intentional! I love Phineas, he's a nice guy, and I just wanna pinch his cute little cheeks all the time; he's part of why I watched the show, which is good cause he's the main character along with Ferb. As such, I like having fun with him.**

 **Basically, in this universe, he's still the same, fun-loving Phineas with a good heart, but he's got the curiosity that would murder plenty of cats. His childish mindset often pushes him to do rather foolish things, especially when he's alone without Ferb to keep him firm on the ground. He's a dreamer, and sometimes dreamers reach too far to the sun.**

 **I also learned that innocence can actually be a fault; basically, it means that you think there's good in everyone…when that's not actually true. This makes Phineas very gullible. I mean, c'mon, he followed a stranger into the ruins, a MONSTER no less! He's lucky it was Toriel, otherwise we'd be having a stranger-danger situation here. O_O**

 **Heck, now that I think about it, doesn't Frisk know better than to talk to strangers? Maybe that's why he was mostly silent throughout the game…XD**

 **Anyways, I'm sorry again for taking so long. I'm trying to make updates on this weekly, but I'm not perfect as you may be able to tell. XD**

 **I hope you enjoyed! Please, review, follow, fave, and have a fantastic day!**

 **-GTS**


	4. Chapter 4: The Ruins

… **So…you remember how my grandpa (who I called and still call Papa) passed away? Well, my grandma/Nani has gone to join him and the Lord Jesus in heaven...it's been a hard year. It's been a hard since 2015 and still pushing onward to 2016 and probably further on. I'm sorry that I'm being such a downer, but…I just need some comfort right now.**

 **No, I'm not asking you guys to feel sorry for me or have me expect you to treat me any different; it's life. I believe that she's in heaven with my/our Lord and Savior Jesus Christ, and is with her family and husband celebrating and praising Him forevermore. She's not suffering any longer and I'm happy for that. I just didn't think she'd go this soon.**

 **Even my parents thought that she'd stay for a while longer; we thought that this would be a year for mourning. God just had other plans…and it really showed. Nani just faded after Papa's funeral; she was losing weight, getting sickly to the point of being hospitalized in April, etc. The point is, Papa was her rock, and it obviously affected her along with other things such as her older sister dying soon after.**

 **My Nani touched many people, and so many people came to mourn for her; I knew how amazing of a grandmother she was, but I never stopped to wonder how great of a person she was until after she was finally gone. I'm so glad for her life, and I'm blessed that I had a grandparent like her. I only wish…that they blessed and made her a frigging Saint, because DANG IT she deserved it (she's Catholic, btw; I, however, am a Protestant Christian).**

 **So, it's been pretty hard, and her sickness was one of the reasons why I haven't been writing much. I've been using the computer as a means for school and comfort/distraction; I don't really like thinking about death on account of how it affected me last time this happened, but it's something that we all have to deal with and so I just have to accept it. Thank you all for your support and I'm sorry for the delay.**

 **Now…let's continue this, shall we?**

 _Phineas and Ferb are owned by Dan Povenmire and Jeff "Swampy" Marsh_

 _Undertale is owned by Toby Fox©_

 **Enjoy~.**

 **P/F/P/F**

 **Chapter 4: The Ruins**

 **(~)**

"Aaaaand…done!"

Phineas rose up his screwdriver and took a look at his phone. No longer a walkie-talkie sort of device, it had been completely transformed into a flip-phone with an orange and blue cover with silver linings. The antenna had been replaced by a stub where it once was. Phineas smiled.

"Alright, let's see if it works," Phineas said, dialing on his cell, "Hm…wait," he paused, "How would a phone work underground? Is there even wi-fi down here?"

Phineas looked up at the ancient ceiling and stood to his feet, wandering as he continued to stare up. Maybe there were some wires, or something. Phineas didn't exactly know how it worked in the Underground, or even how it would work, but he would find out, darn it. He wasn't really paying attention, however, and was surprised when his phone started to ring.

Phineas looked down to his phone, opened it, and put it to his awkwardly place ear. "Hello?" he asked.

Toriel voiced through, "Hello? This is Toriel. You have not left the room, have you?"

Phineas paused, lifted his head up once again, and took a survey of his surroundings. How did he wander out here, he wondered as he realized he was no longer standing beside the pillar and had entered another spacing. He didn't get a chance to answer Toriel's question, as she went on:

"There are a few puzzles ahead that I have yet to explain. It would be dangerous to try to solve them yourself. Be good, alright?"

Phineas was silent for a few seconds before answering, "Okay. I will."

"I will be back very soon, my child! Just need to get a few things…"

The phone clicked off. Phineas placed the device into his pocket, his smile, though well-meaning to the common eye, would be turning slightly devious to someone who could read his thoughts. "Well…I'm already out here," he said, "It wouldn't hurt to look around for a tiny bit."

Not being able to fight off his curious-driven temptation any further, Phineas decided that he should, no, that he _must_ explore the place further! Who knows? Perhaps he would find his friends that way. Phineas, pleased with his reasoning with himself, stepped forward.

"Ribbit, ribbit."

Phineas paused at the familiar sound croaking beside him. He turned slowly to none other than a Froggit. Phineas stared at it, and their gazes seemed to intensify. Phineas blinked, and underneath the fake body, so did the Froggit. "…Uh…" Phineas rose up a hand and waved, "Hello?"

"Ribbit, ribbit."

Phineas blinked again, wondering if this was the same Froggit that attacked him from before. Somehow he doubted it, given that Toriel had gone through there already. Phineas assumed that the Froggit who had tackled into him was hiding somewhere.

"Ribbit, ribbit (Excuse me, human)."

Phineas gave a slow, awkward smile. What was he supposed to say? "I like the way you sound," he managed to say, "It's…very frog-like."

The Froggit did not seem to care about what Phineas said and continued croaking. Phineas chuckled more nervously.

"(I have some advice to give to you about battling monsters,)" the Froggit said, "(If you **act** a certain way or **fight** them until you've almost defeated them…)" it craned its fake body towards Phineas, "(They might not want to battle you anymore. If a monster does not want to fight, please…)" it bowed its 'head', "(Use some **mercy** , human.) RIBBIT."

Phineas tilted his head at the creature who continued to stare at him. "…I have no idea what it's saying," he admitted to himself before looking towards, what a surprise, another room that stood beside the Froggit. Phineas smiled. "Ooh, what's in there?" he asked as he walked around the Froggit into the room.

The Froggit watched as the human entered, and he sighed as he knew very well that the human understood him as little as he understood the human. "Ribbit…(Curse my inability of speech…such irony…such is fate…)"

Phineas looked around possibly the smallest room in the entire building thus far. He looked over to the water on his left and on his right, as well as at the plant life. He would've immediately been bored by this display had it not been for the small pillar holding a bowl of candy. He grinned, ignoring the square of dead leaves pinned around it. He peered into the bowl, and saw a small, tiny piece of paper that said "take one".

Phineas stared and let out a calming breath. "I cannot disobey the words of paper," he said, as if above transgression itself, and quoted Ferb, "Thine is law."

In spite his noble words however, Phineas snuck one, and then another piece of candy. He looked around to make sure no one saw him practically break the law.

 _How disgusting…_

Phineas rose his head up at the sound in shock, looking around again. No one. Not a single person or thing was there. He glared up to where he _thought_ the sound was coming from. "Fine, fine," he groaned, "I'll put it back…"

Phineas reached out to the bowl, in an attempt to place the candy back. As if it were a magnet, however, another piece latched itself to his hand. Phineas stared at the three pieces of candy in his hand.

 _You feel like the scum of the earth…_

Phineas gasped, looking back up to the sound, wherever it was, and felt his chest tightened. He no longer craved the sugary sweets and attempted to force them all back down into the bowl, but the force caused him to tip the bowl of candy over, soiling it all. Phineas stared in horror, at the pile of sweetness gone to waste, and the _four pieces of candy_ in his hands.

 _Look at what you've done._

Full of guilt and terror, Phineas ran out of the room, his eyes widened as he shrieked. He put the pieces of candy in his pocket, deciding that he would not let their fallen brethren die in vain. Once Phineas had calmed himself, he looked back to the room, dumbfounded. "Okay…so…that happened," Phineas looked down the path, seeing more dead leaves on the ground.

As Phineas went, he stepped on the leaves, remembering the autumn time when he, Ferb, and his friends would jump into a giant hill of leaves that he and his brother had made themselves for them to play in. Candace would assume that to be foul play, of course, but no one else seemed to mind, even if the pile of leaves had been the height of mountains, even taller than Mt. Ebott. Candace thought everything was foul-play, didn't she? Ever since their parents…left…she had been nosier than ever. Nosey enough for even someone as oblivious as Phineas to take notice.

Phineas rolled his eyes as he began to playfully crinkle through the leaves as he went along, forgetting about his recent sins against the heavens. _It filled him with determination_.

Suddenly, he tripped over, falling onto the ground face first. Phineas pushed himself up, rubbing his nose before looking behind him to see a small, sobbing figure. Phineas gasped at the monster, a creature with the appearance of an insect with two drooping antennae, two small wings, and two little arms and legs. Its body shape resembled that of a ghost. Its current expression was tear-filled sadness, with an open frowning mouth and eyebrows. It was crying, or rather whimpering, as softly at it could.

Phineas reached out to the creature. "I-I'm so sorry!" he said, "Are you o-?"

Halfway through Phineas' words, the creature burst into tears and flew away. Phineas watched as it fled, and ran after it immediately, unaware that it was leading him further away from where he was supposed to be. "WAIT!" he called out, "I don't want to hurt you! I just wanna talk!"

Phineas chased after the sobbing monster, but not for long. For as soon as Phineas reached a certain point in the path, the floor below him crumbled, sending him falling. He landed on an even bigger pile of red colored leaves. Unlike the flowers that had broken his fall before, however, the leaves did less, and even though they cushioned the fall, he still felt sore. Luckily, no real damage could be caused by such a short fall. He rubbed his buttocks, groaning.

"Ugh…what's with me falling today?" Phineas asked himself. He looked up. "Was that a trap? I think that was a trap!"

 _Well, no shit, Sherlock, what was your first clue?_

As the boy looked around, he quickly found two flights of stairs, one of one side of the pile of leaves he currently resided on, and one on the other. Phineas took the other flight of stairs, and quickly got out of his predicament. However, the sad creature he was chasing after was nowhere to be seen. He glared at the "trap". Now that he thought about it, it served more as a nuisance than an actual trap, especially given the stairs that led outside of it.

Worry filled Phineas for the poor creature, and he went forward. The next room consisted of a rock lined up in front of some kind of panel, while further down was a barricade of spikes coming out of the floor. Phineas didn't have the chance to further survey the room when his phone rang again and he answered.

"Hello? This is Toriel," his friend said, "For no reason in particular…Which do you prefer? Cinnamon or Butterscotch?"

Phineas almost went with butterscotch, but it reminded him of the bowl of candy that he knocked over (honestly, who on this earth would feel this guilty about something like that?), and went with cinnamon instead. The speed of his answer made Phineas believe for a moment that Toriel would've thought something was wrong, but instead she spoke evenly, "Oh, I see. Thank you very much!"

And with that, Toriel hung up. Phineas smiled as he continued to look around before the phone rang again as soon as he took another step.

"Hello, this is Toriel," the lady monster said, "You do not DISLIKE butterscotch, do you? I know what your preference is…would you turn up your nose if you found it on your plate?"

"Well…I'm fine with either one," Phineas admitted with a patient smile.

"Right, right," Toriel said, and Phineas could hear her nod through the phone, "Thank you for being patient, by the way."

The phone hung up, and Phineas sweated a little. Should he really keep going now? "Well…I should find that flying monster and see if it's okay," he reasoned, "Besides…" he smiled at the puzzle, "I'd like to give this a try."

In spite knowing that the obvious route would be to push the rock forward, Phineas' instincts went to yet another sign on the wall next to him. He frowned at the text, not sure what he was initially expecting.

 _ **Three out of four grey rocks recommend you to push them.**_

Without a clue as to what the sign meant, Phineas shrugged and went to the grey raggedy stone that was about a sliver shorter than him. Despite the size, the rock was surprisingly easy to push onto the panel, which caused the spikes to lower themselves into the ground. Phineas smiled as he walked passed the floor and down the next hall.

"Man, this place is huge," Phineas commented, "It's kinda nice, though, for a Ruins. Though…I would've thought Ruins would look more…uh…ruinous…"

He paused and felt his jaw drop as before him was a long pathway of unstable ground, covered in cracks not too different from the ones that sent him careening downward while he chased after the flying monster. Phineas stared and he examined the floor before him. Squinting, he carefully took a step forward and to his surprise saw that it was sturdy enough to support his weight. He smiled and took another step, only to find himself once again falling through the floor and landing on yet another pile of leaves, place intricately for reasons Phineas didn't understand. He groaned.

"Time to do this the lazy man's way…"

Phineas took out his phone once again and dialed a seemingly random number. For whatever reason, a large propeller slipped out, and proceeded to lift Phineas up from the ground, out of the trap and over the rest of the dangerous looking pathway. He reached the other side and continued forward, shutting off the propellers as he did.

In the next room was a set of three rocks, much like the first movable one in the other room. In front of the rocks was an even thicker set of spikes coming out of the floor than the last. Phineas looked immediately proceeded to push the rocks. "Hm…you know," Phineas thought to himself as he finished pushing the second of the three rocks, "I just realized something…if Miss Toriel went through this path, then she must've gone through these puzzles. How in the world did they reset on their own?"

Before he could come up with a logical answer, suddenly, the third rock of which he proceeded to push suddenly spoke. "WHOA there, pardner," it spoke, "Who said you could push me around?"

"Oh, I'm sorry," Phineas apologized, "I didn't realize you were…"

Phineas didn't know why, but in spite the fact that rocks indeed have no faces the rock appeared to be eyeing him up and down in a way that made it seem displeased. "Didn't know that I was _**what?**_ " it asked with…gritted teeth? This place was getting weirder by the minute.

"N-nothing," Phineas quickly said, clearly his throat, "Nothing at all, nothing…at all…uh…do you think you can move, please? I need to get through the puzzle."

The rock hummed in blaring thought. "So you're ASKIN' me to move over?" it asked to verify, though it didn't wait for Phineas to answer, "Okay, just for you, pumpkin."

The rock inched only a little forward towards the dial, and stopped immediately. Phineas blinked, looking back and forth from rock and to the panel before poking at the rock again. "Excuse me," he said politely, "But I'm gonna need you to move a little more, please."

The rock hummed louder than the last time, and Phineas assumed that it must've had hard of hearing. He couldn't blame it, since it appeared to have no ears at all. "You want me to move some more?" it asked, "Alrighty, how's this?"

The rock moved once again, but off of the alignment of the panel, and onto the side. Phineas stared at the rock, shook his head, and said, "Uh…no, no, I need you to get on the panel, please. You're going the wrong way."

The rock hummed, louder than the last two times. "That was the wrong direction?" it asked, "Okay, I think I got it."

With that, the rock proceeded to move back to the alignment and slid all the way onto the panel, allowing the spikes to hide into the ground and allow passage. Phineas grinned, nodded at the rock, and proceeded forward. Before he could continue on his merry way, however, the spikes shot up suddenly, nearly piercing Phineas' foot had he not stumbled back. He looked over to the rock once again and saw that it had moved off of the panel. Phineas went back over to the rock, which seemed to sigh as if to ask what the boy wanted from it now.

"You need to stay there a little bit longer, sir…ma'am…yoooouuu…" Phineas explained awkwardly.

The rock let out the loudest thoughtful hum that Phineas had ever heard. It seemed to put all of its strength into the hum. Why such a thing filled him with determination was beyond even him. "You wanted me to STAY there," it concluded with another sigh, "You're giving me a real workout."

The rock once again slid back onto the panel, and the spikes once again retreated into their respective holes. Phineas thanked the rock before continuing on his way to the next room. To Phineas' surprise, it was not another puzzle, but instead consisted of a single table that had cheese on it. He went over and tried to pull the cheese off, but realized that it had been there for so long that it was now stuck onto the table. Phineas looked over to see a mouse hole on the wall, and realized that a mouse must be trying desperately to get the cheese.

Knowing the mouse may one day leave his hole and get the cheese… _it filled Phineas with determination._

And so, Phineas continued forward with his spirits rising as optimistically as it did usually. So far, these puzzles were a breeze, and the encounters he had made with other monsters…now that he thought about it, wasn't he forgetting something? Ah well. He'd remember later.

Phineas paused as he looked at the newest form before him and stared blankly. What it looked like was a child with a sheet over his head, with holes to see through. Of course, this looked more realistic as far as cartoonish looking ghosts were, lying down, staring up at the ceiling lifelessly.

Well, not lifelessly. He seemed to be breathing. In fact, he seemed to be sleeping. With his eyes opened.

"…Hello!" Phineas greeted, waving, "I'm very sorry. But do you think you can…move out of the way?"

"ZZZZZZZZZZZZZZZ…" the ghost-like pillow sheet said/snored, "ZZZZZZZZZZZZZZ…ZZZZZZZZZZ…(are they gone yet?)… ZZZZZZZZZZZZZZZ…"

Phineas stared as the ghost continued to say "z" loudly, pretending to sleep. The child blinked and looked around, shuffling a bit as he waited for an actual answer. After waiting a bit, he tried again. "Hello? Mr. Ghost-Pillow-Sheet-Person?" he asked with a louder tone, "May you please move?"

"…ZZZZZZZZZZZZZZZ…"

"…Wait…if he's a ghost…then I can just walk right through him!"

With that mindset, he decided to move forward and continue on his-

 _Bump_

Phineas tripped up at the tangible ghost being and fell right on top of him, shocking the ghost up into the air (though his version of "shocked" was very monotone and slow, not very emotional at all). The redheaded boy was flipped onto his back as the ghost stared down at him with large black and white eyes that looked like they may burst into tears at any moment. With a light "bing" sound, Phineas paled at the sight of a red heart popping out of his chest, floating in the air.

 _Here comes Napstablook._

 **A/N:**

 **This seemed a good place to end this chapter, and again I must apologize profusely for how long these updates are taking. I didn't expect this crossover to be so…successful. Like, I'm very happy that so many of you like this, even though so far it's just me looking at a let's play of the game and writing down the script…I really need to find a way to put a PnF spin to this.**

 **And yes, Phineas is a bit OOC here…but just a bit. My excuse is that this is probably like one of those Time-Shift episodes, or that Star Wars crossover (which was so awesome, by the way); they were all slightly different because it all took place in AUs within themselves, so they were allowed to be a little different…yes that's a weak excuse, please forgive me.**

 **Anyways, I hope you all enjoyed, and I hope you all had a blessed day/afternoon/evening/night! Carpe Diem, and God Bless you all!**

 **-GTS**


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